Sodic Soil Amelioration using Lime and Gypsum - Five Years of Results at Gunning Gap


Research organisaton

Trial details

Researcher(s) Ken Motley (NSW DPI) and Andrew Rice (Ivey ATP)
Year(s) 2004
Contributor Central West Farming Systems
Trial location(s) Site 1, Gunning Gap, NSW
Sodic Soil Amelioration using Lime and Gypsum - Five Years of Results at Gunning Gap locations

To demonstrate the production and associated economic benefits from ameliorating soil acidity over the long term.

Key messages
  • The application of lime and gypsum to a sodic soil has produced improvements in soil structure observable to visitors of the trial site.
  •  Improvement in soil structure have been associated with variable responses in grain yield and quality across years, apparently in response to varying available soil moisture over the last 5 crop years (2000 to 2004).
  • Yield increases with soil amelioration are associated with years where crop growing conditions were conducive to high yield and/or reasonable levels of sub soil moisture were available to the crop (years 2001 and 2002).
  • In contrast, barley yield declines of 40% - 80% and quality downgrades have occurred in the last two very dry years (2003 and 2004). This is thought to be due to the soil amelioration treatments promoting additional early season vegetative growth but being followed by severe spring conditions leading to the crop "haying off”.
  • The trial has sown no economic benefit of soil amelioration in 5 years.
Lead research organisation Central West Farming Systems
Host research organisation N/A
Related program N/A

These trials were conducted as part of the CWFS Regional Site program. The trial sites were supported by the Grain Growers Association and GRDC. Greg Gibson (NSW DPI), Sharon Taylor (CWFS) and Allan
L’Estrange (CWFS) provided invaluable technical assistance. The data was analysed by Helen Nicol (consulting statistician). Thanks go to Mark Judson (trial co-operator) for his cooperation over the last 5 years.

Other trial partners Not specified
Download the trial report to view additional trial information


Crop type Wheat
Treatment type(s)
  • Soil amelioration
Trial type Demonstration
Trial design Replicated

Gunning Gap 2004

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Download the trial report to view additional method/treatment information

Trial results Table 1

# Treatment 1
Screenings (%) Protein (%) Grain yield (t/ha)
1 Nil 13.5 14.6 0.68
2 2 Lime 23.2 17.1 0.46
3 Albrecht 34.7 18.2 0.42
4 6 Lime 38.6 18.7 0.39
5 8 Lime 36.5 18.4 0.4
6 4 Gypsum 20 16.5 0.61

Grain yield t/ha


Protein %


Screenings %

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 1, Gunning Gap, NSW Not specified
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 1, Gunning Gap, NSW Chromosol
National soil grid Source
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties



Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Site 1, Gunning Gap NSW


Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.